I am using Crystal 10.  I am trying to find the total amount of time field techs spend at a site for a case.  For example if techs visit a site four different times we need to find the duration of each visit to determine the grand total of time at the site.  The next case could have one or more visits or even zero visits.

 The table I am using lists an event (Arrive, Depart, Close Case, etc - may not be related to the field tech - such as the calls to help center or dispatching to field tech) with a time/date stamp for the event plus site id, case id, tech name, etc.  So for the example above there would be four "Arrive" events and four "Depart" events (unless the last interaction was "Close Case" then there would be three "Departs" and the last would be "Close Case").

 The records are currently being grouped by site id and then case id.